Lymphocyte activation assays
To analyze the activation of CD4+ T, CD8+ T and B cells after immunization, we assessed the proportion of CD69+ splenic lymphocytes. CD69 is one of the earliest lymphocyte surface markers detected after antigen stimulation [19]. The proportions of CD4+ CD69+ T (Fig. 6A-B), CD8+ CD69+ T (Fig. 6C-D) and CD19+ CD69+ B (Fig. 6E-F) cells in the ZI-△-PA-GEM group were significantly higher than those in the control group. This result indicated that ZI-△-PA-GEM with a complex adjuvant of ISA201 VG and poly(I:C) promoted T/B cell activation.
Next, we detected the proportion of central memory T cells (TCMs; CD44+ CD62L+) among splenic lymphocytes. As shown in Fig. 7, the proportion of TCMs among CD4+ T (Fig. 7A-B) and CD8+ T (Fig. 7C-D) cells was significantly increased by ZI-△-PA-GEM, ZI-JE-△-PA-GEM and ZI-GP-△-PA-GEM.